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samba-mirror/source3/smbd/conn.c
Jeremy Allison f92bacbe21 s3/smbd: Use after free when iterating smbd_server_connection->connections
Change conn_free() to just use a destructor. We now
catch any other places where we may have forgetten to
call conn_free() - it's implicit on talloc_free(conn).

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15128

Based on code from Noel Power <noel.power@suse.com>.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Noel Power <npower@samba.org>

Autobuild-User(master): Noel Power <npower@samba.org>
Autobuild-Date(master): Wed Aug 17 09:54:06 UTC 2022 on sn-devel-184
2022-08-17 09:54:06 +00:00

268 lines
7.7 KiB
C

/*
Unix SMB/CIFS implementation.
Manage connections_struct structures
Copyright (C) Andrew Tridgell 1998
Copyright (C) Alexander Bokovoy 2002
Copyright (C) Jeremy Allison 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "lib/util/bitmap.h"
static void conn_free_internal(connection_struct *conn);
/****************************************************************************
* Remove a conn struct from conn->sconn->connections
* if not already done.
****************************************************************************/
static int conn_struct_destructor(connection_struct *conn)
{
if (conn->sconn != NULL) {
DLIST_REMOVE(conn->sconn->connections, conn);
SMB_ASSERT(conn->sconn->num_connections > 0);
conn->sconn->num_connections--;
conn->sconn = NULL;
}
conn_free_internal(conn);
return 0;
}
/****************************************************************************
Return the number of open connections.
****************************************************************************/
int conn_num_open(struct smbd_server_connection *sconn)
{
return sconn->num_connections;
}
/****************************************************************************
Check if a snum is in use.
****************************************************************************/
bool conn_snum_used(struct smbd_server_connection *sconn,
int snum)
{
struct connection_struct *conn;
for (conn=sconn->connections; conn; conn=conn->next) {
if (conn->params->service == snum) {
return true;
}
}
return false;
}
/****************************************************************************
Find first available connection slot, starting from a random position.
The randomisation stops problems with the server dieing and clients
thinking the server is still available.
****************************************************************************/
connection_struct *conn_new(struct smbd_server_connection *sconn)
{
connection_struct *conn = NULL;
conn = talloc_zero(NULL, connection_struct);
if (conn == NULL) {
DBG_ERR("talloc_zero failed\n");
return NULL;
}
conn->params = talloc(conn, struct share_params);
if (conn->params == NULL) {
DBG_ERR("talloc_zero failed\n");
TALLOC_FREE(conn);
return NULL;
}
conn->vuid_cache = talloc_zero(conn, struct vuid_cache);
if (conn->vuid_cache == NULL) {
DBG_ERR("talloc_zero failed\n");
TALLOC_FREE(conn);
return NULL;
}
conn->connectpath = talloc_strdup(conn, "");
if (conn->connectpath == NULL) {
DBG_ERR("talloc_zero failed\n");
TALLOC_FREE(conn);
return NULL;
}
conn->cwd_fsp = talloc_zero(conn, struct files_struct);
if (conn->cwd_fsp == NULL) {
DBG_ERR("talloc_zero failed\n");
TALLOC_FREE(conn);
return NULL;
}
conn->cwd_fsp->fsp_name = synthetic_smb_fname(conn->cwd_fsp,
".",
NULL,
NULL,
0,
0);
if (conn->cwd_fsp->fsp_name == NULL) {
TALLOC_FREE(conn);
return NULL;
}
conn->cwd_fsp->fh = fd_handle_create(conn->cwd_fsp);
if (conn->cwd_fsp->fh == NULL) {
DBG_ERR("talloc_zero failed\n");
TALLOC_FREE(conn);
return NULL;
}
conn->sconn = sconn;
conn->force_group_gid = (gid_t)-1;
fsp_set_fd(conn->cwd_fsp, -1);
conn->cwd_fsp->fnum = FNUM_FIELD_INVALID;
conn->cwd_fsp->conn = conn;
DLIST_ADD(sconn->connections, conn);
sconn->num_connections++;
/*
* Catches the case where someone forgets to call
* conn_free().
*/
talloc_set_destructor(conn, conn_struct_destructor);
return conn;
}
/****************************************************************************
Clear a vuid out of the connection's vuid cache
****************************************************************************/
static void conn_clear_vuid_cache(connection_struct *conn, uint64_t vuid)
{
int i;
for (i=0; i<VUID_CACHE_SIZE; i++) {
struct vuid_cache_entry *ent;
ent = &conn->vuid_cache->array[i];
if (ent->vuid == vuid) {
ent->vuid = UID_FIELD_INVALID;
/*
* We need to keep conn->session_info around
* if it's equal to ent->session_info as a SMBulogoff
* is often followed by a SMBtdis (with an invalid
* vuid). The debug code (or regular code in
* vfs_full_audit) wants to refer to the
* conn->session_info pointer to print debug
* statements. Theoretically this is a bug,
* as once the vuid is gone the session_info
* on the conn struct isn't valid any more,
* but there's enough code that assumes
* conn->session_info is never null that
* it's easier to hold onto the old pointer
* until we get a new sessionsetupX.
* As everything is hung off the
* conn pointer as a talloc context we're not
* leaking memory here. See bug #6315. JRA.
*/
if (conn->session_info == ent->session_info) {
ent->session_info = NULL;
} else {
TALLOC_FREE(ent->session_info);
}
ent->read_only = False;
ent->share_access = 0;
}
}
}
/****************************************************************************
Clear a vuid out of the validity cache, and as the 'owner' of a connection.
Called from invalidate_vuid()
****************************************************************************/
void conn_clear_vuid_caches(struct smbd_server_connection *sconn, uint64_t vuid)
{
connection_struct *conn;
for (conn=sconn->connections; conn;conn=conn->next) {
if (conn->vuid == vuid) {
conn->vuid = UID_FIELD_INVALID;
}
conn_clear_vuid_cache(conn, vuid);
}
}
/****************************************************************************
Free a conn structure - internal part.
****************************************************************************/
static void conn_free_internal(connection_struct *conn)
{
vfs_handle_struct *handle = NULL, *thandle = NULL;
struct trans_state *state = NULL;
/* Free vfs_connection_struct */
handle = conn->vfs_handles;
while(handle) {
thandle = handle->next;
DLIST_REMOVE(conn->vfs_handles, handle);
if (handle->free_data)
handle->free_data(&handle->data);
handle = thandle;
}
/* Free any pending transactions stored on this conn. */
for (state = conn->pending_trans; state; state = state->next) {
/* state->setup is a talloc child of state. */
SAFE_FREE(state->param);
SAFE_FREE(state->data);
}
free_namearray(conn->veto_list);
free_namearray(conn->hide_list);
free_namearray(conn->veto_oplock_list);
free_namearray(conn->aio_write_behind_list);
ZERO_STRUCTP(conn);
}
/****************************************************************************
Free a conn structure.
****************************************************************************/
void conn_free(connection_struct *conn)
{
TALLOC_FREE(conn);
}
/*
* Correctly initialize a share with case options.
*/
void conn_setup_case_options(connection_struct *conn)
{
int snum = conn->params->service;
if (lp_case_sensitive(snum) == Auto) {
/* We will be setting this per packet. Set to be case
* insensitive for now. */
conn->case_sensitive = false;
} else {
conn->case_sensitive = (bool)lp_case_sensitive(snum);
}
conn->case_preserve = lp_preserve_case(snum);
conn->short_case_preserve = lp_short_preserve_case(snum);
}